For example, a fuel injection pipe coupled to an oil injection port is connected to a fuel tank of a automobile, and a flap valve device is sometimes provided as a check valve to the fuel injection pipe at its opening on the downstream side. The flap valve is arranged to open to let the fuel flow into the tank during oil feeding, and close after the completion of oil feeding to prevent backflow of the fuel into fuel injection pipe.
As a flap valve device of this conventional type, Patent Document 1 describes a check valve for preventing backflow of fuel that includes a cylindrical case, a bearing portion provided to the case at its end on the downstream side, a valve element integrally including a shaft portion that is pivotally supported by the bearing, and an urging means for urging the valve element in a closing direction toward the opening portion of the case.
The bearing portion is provided to a supporting member that is separate from the case. A clip portion provided to the supporting member is engaged with a flat seat portion provided to the case at its end portion on the downstream side, whereby the clip portion is attached to the case to make the bearing portion disposed at the end portion on the downstream side of the case.
The case is made from metal while the supporting member and the valve element are made from a resin material.